November 20 is the 324th day of the year (325th in leap years) in the Gregorian calendar. There are 41 days remaining until the end of the year. This date is slightly more likely to fall on a Tuesday, Friday or Sunday (58 in 400 years each) than on Wednesday or Thursday (57), and slightly less likely to occur on a Monday or Saturday (56).

1979 – Grand Mosque seizure: About 200 Sunni Muslims revolt in Saudi Arabia at the site of the Kaaba in Mecca during the pilgrimage and take about 6000 hostages. The Saudi government receives help from Pakistani special forces to put down the uprising.

1980 – Lake Peigneur drains into an underlying salt deposit. A misplaced Texaco oil probe had been drilled into the Diamond Crystal Salt Mine, causing water to flow down into the mine, eroding the edges of the hole.